In case BFS in a nutshell isn't enough for your reading pleasure, this is my own attempt to put into a nutshell everything I know, or think, about BFS (unless I forgot something, in which case I guess maybe I don't know it anyway 
) ).
ALS
BFS aint it, so how about we stop wasting our time talking about it so much and talk about stuff that's actually relevant (doesn't apply to newcomers who may still need to get over that hurdle).
Voltage Gated Potassium Channel (VGKC)
BFS is presumed to be an autoimmune attack against the VGKC. When a motor nerve impulse reaches the nerve terminal, the calcium and sodium channels open the gates which allow the neurotransmitter acetylcholine to flow to the muscle. This causes the muscle to contract. Afterwards, it's the potassium channel's job to close the gates back up. If the potassium channel fails to do its job, the muscle fiber will stay active.
There are 2 different tests for VGKC antibodies. The most widely available is an "immunoprecipitation" assay. Unfortunately, it's not a very sensitive test and has a lot of false negative results. The other test, a "molecular-immunohistochemical" assay, is much more sensitive but not available to the vast majority. (Few people on aboutBFS.com seem to have had either test.)
There are several treatments for VGKC autoimmunity (reserved for those who are significantly affected):
1) Plasma exchange (strips antibodies out of blood) - works well, but relief is only temporary; it's a slow in-patient procedure.
2) IVIg (injection of certain antibodies into the bloodstream) - doesn't work very well on PNH; expensive.
3) Immunosuppressants (drugs that suppress the immune system so that it doesn't produce so many antibodies) - works well for some but not for others; body becomes vulnerable to infection because of the weakened immune system.
4) Anticonvulsant drugs (carbamazepine, phenytoin, and lamotrigine, which suppress the sodium channel, preventing the muscle from receiving as much acetylcholine) - relieves twitching in many; drugs may have adverse side effects; doesn't address the underlying problem.
Neuromyotonia (NMT)
BFS is considered by some experts to be a mild form of neuromyotonia (aka Isaacs' syndrome), so the umbrella term "peripheral nerve hyperexcitability" (PNH) is the preferred term for all conditions on the continuum.
The features of NMT can include muscle twitching, muscle cramping, muscle stiffness, pseudomyotonia (delayed muscle relaxation), pseudotetany (constant muscle contraction), sensory symptoms, CNS symptoms, muscle hypertrophy (enlargement), muscle wasting, autonomic symptoms, and symptoms triggered by exercise.
Note that one of the symptoms is weakness (and does not say perceived weakness). The explanation for the weakness is that muscles that are constantly active get tired, and it is the muscles that are the most active that become the weakest. (I think it goes without saying that this type of weakness is not permanent.)
Another symptom is pseudotetany, which is sometimes confused with spasticity. Spasticity is caused by a lack of signal from the brain. It's the CNS (brain) that sends a signal to inhibit muscle contractions. When there is no signal from the brain, the lower motor neurons have a hayday and tell the muscles to go ahead and contract all they want. Tetany is similar to spasticity in its manifestation, but different in its cause. Tetany happens in the peripheral nerve level, not in the brain or spinal cord. The difference between tetany and pseudotetany is that tetany is caused by a dysfunction of the sodium channel, whereas pseudotetany is caused by a dysfunction of the potassium channel.
Paraneoplastic conditions
Some cases of neuromyotonia (15% or so) are caused by a cancerous tumor (neoplasm) somewhere in the body. The term "paraneoplastic" is used to refer to conditions that are indirectly caused by a neoplasm. Usually the neoplasm is a thymoma (tumor of the thymus gland); occasionally it's lung cancer; rarely it's plasmacytoma (multiple myeloma except that it's single rather than multiple). Since BFS is considered to be a mild form of neuromyotonia, it stands to reason that some cases of BFS may be associated with a tumor, although the percentage is probably lower than it would be for full-blown neuromyotonia.
Here's the reason why tumors can cause autoimmune diseases. The tumor first develops, which then causes the immune system to launch an attack against the tumor. From the immune system's point of view, something in the tumor coincidentally appears identical to some other type of body tissue, so those tissues end up being attacked as well.
Interestingly, people with this type of autoimmune attack tend to have a better prognosis than those with the same type of tumor but without the autoimmune attack. That's because those with the autoimmune attack have more robust immune systems which are fighting off the tumor. (Apparently those w/o the autoimmune attack have weaker immune systems and are more likely to succomb to the cancer.)
The term "benign"
I consider the term "benign" to be misleading. While BFS IS benign in that it isn't fatal, that doesn't mean that it isn't a real illness with a real cause. It is real, and it does have a cause. It can be somewhat disabling, and it can also be associated to things that are serious. Just ruling out ALS isn't enough. Just because you don't have ALS doesn't mean you shouldn't get diagnosed, and possibly treated, for what it is that you do have.
According to Dr. Hart, "...all patients presenting with acquired PNH should have a serum autoantibody screen that includes VGKC and AChR antibodies, plus glucose and thyroid function tests to help exclude other autoimmune diseases. Secondly, because PNH can be paraneoplastic, it is important to search for an underlying thymoma or lung cancer."
) ).ALS
BFS aint it, so how about we stop wasting our time talking about it so much and talk about stuff that's actually relevant (doesn't apply to newcomers who may still need to get over that hurdle).
Voltage Gated Potassium Channel (VGKC)
BFS is presumed to be an autoimmune attack against the VGKC. When a motor nerve impulse reaches the nerve terminal, the calcium and sodium channels open the gates which allow the neurotransmitter acetylcholine to flow to the muscle. This causes the muscle to contract. Afterwards, it's the potassium channel's job to close the gates back up. If the potassium channel fails to do its job, the muscle fiber will stay active.
There are 2 different tests for VGKC antibodies. The most widely available is an "immunoprecipitation" assay. Unfortunately, it's not a very sensitive test and has a lot of false negative results. The other test, a "molecular-immunohistochemical" assay, is much more sensitive but not available to the vast majority. (Few people on aboutBFS.com seem to have had either test.)
There are several treatments for VGKC autoimmunity (reserved for those who are significantly affected):
1) Plasma exchange (strips antibodies out of blood) - works well, but relief is only temporary; it's a slow in-patient procedure.
2) IVIg (injection of certain antibodies into the bloodstream) - doesn't work very well on PNH; expensive.
3) Immunosuppressants (drugs that suppress the immune system so that it doesn't produce so many antibodies) - works well for some but not for others; body becomes vulnerable to infection because of the weakened immune system.
4) Anticonvulsant drugs (carbamazepine, phenytoin, and lamotrigine, which suppress the sodium channel, preventing the muscle from receiving as much acetylcholine) - relieves twitching in many; drugs may have adverse side effects; doesn't address the underlying problem.
Neuromyotonia (NMT)
BFS is considered by some experts to be a mild form of neuromyotonia (aka Isaacs' syndrome), so the umbrella term "peripheral nerve hyperexcitability" (PNH) is the preferred term for all conditions on the continuum.
The features of NMT can include muscle twitching, muscle cramping, muscle stiffness, pseudomyotonia (delayed muscle relaxation), pseudotetany (constant muscle contraction), sensory symptoms, CNS symptoms, muscle hypertrophy (enlargement), muscle wasting, autonomic symptoms, and symptoms triggered by exercise.
Note that one of the symptoms is weakness (and does not say perceived weakness). The explanation for the weakness is that muscles that are constantly active get tired, and it is the muscles that are the most active that become the weakest. (I think it goes without saying that this type of weakness is not permanent.)
Another symptom is pseudotetany, which is sometimes confused with spasticity. Spasticity is caused by a lack of signal from the brain. It's the CNS (brain) that sends a signal to inhibit muscle contractions. When there is no signal from the brain, the lower motor neurons have a hayday and tell the muscles to go ahead and contract all they want. Tetany is similar to spasticity in its manifestation, but different in its cause. Tetany happens in the peripheral nerve level, not in the brain or spinal cord. The difference between tetany and pseudotetany is that tetany is caused by a dysfunction of the sodium channel, whereas pseudotetany is caused by a dysfunction of the potassium channel.
Paraneoplastic conditions
Some cases of neuromyotonia (15% or so) are caused by a cancerous tumor (neoplasm) somewhere in the body. The term "paraneoplastic" is used to refer to conditions that are indirectly caused by a neoplasm. Usually the neoplasm is a thymoma (tumor of the thymus gland); occasionally it's lung cancer; rarely it's plasmacytoma (multiple myeloma except that it's single rather than multiple). Since BFS is considered to be a mild form of neuromyotonia, it stands to reason that some cases of BFS may be associated with a tumor, although the percentage is probably lower than it would be for full-blown neuromyotonia.
Here's the reason why tumors can cause autoimmune diseases. The tumor first develops, which then causes the immune system to launch an attack against the tumor. From the immune system's point of view, something in the tumor coincidentally appears identical to some other type of body tissue, so those tissues end up being attacked as well.
Interestingly, people with this type of autoimmune attack tend to have a better prognosis than those with the same type of tumor but without the autoimmune attack. That's because those with the autoimmune attack have more robust immune systems which are fighting off the tumor. (Apparently those w/o the autoimmune attack have weaker immune systems and are more likely to succomb to the cancer.)
The term "benign"
I consider the term "benign" to be misleading. While BFS IS benign in that it isn't fatal, that doesn't mean that it isn't a real illness with a real cause. It is real, and it does have a cause. It can be somewhat disabling, and it can also be associated to things that are serious. Just ruling out ALS isn't enough. Just because you don't have ALS doesn't mean you shouldn't get diagnosed, and possibly treated, for what it is that you do have.
According to Dr. Hart, "...all patients presenting with acquired PNH should have a serum autoantibody screen that includes VGKC and AChR antibodies, plus glucose and thyroid function tests to help exclude other autoimmune diseases. Secondly, because PNH can be paraneoplastic, it is important to search for an underlying thymoma or lung cancer."
There is talk being bandied about by some of your cyber-friends to send you a gigolo for xmas. Something to take your mind off of all this tremendous knowledge. 